Hard drives die too

One thing you can do when you have 25,000 consumer level HDDs running is to amass accurate data on the failure rates of drives. Backblaze has done exactly that and published their findings which match fairly closely to the predicted MTBF pattern of a spike in the beginning of the life cycle as flawed drives fail, a long period of reliability followed by another rise in failures as drives age beyond their expected lifespan. They have told the Register that they intend to follow up with tests on enterprise grade disks to see if the premium you pay is a good investment.

"Cloud backup outfit Backblaze has cobbled together all the data it's gathered from the 25,000 or so disk drives it keeps spinning and drawn some conclusions about just how long you can expect disks to survive in an array."

Any ideas of best economical 7200rpm 3TB drives for creating an 18TB RAID 5 array? Where, when to buy by end of November?

I bought a set of 5 Seagate Barracuda ST3000DM001 last year on Cyber Monday newegg sale, only 1 of the set didn't fail over the last year, and that's without RAID... is Western Digital Black any better?